Command Injection on GMO Flatt Security Research

Remote Command Execution in Google Cloud with Single Directory Deletion

Mon, 23 Mar 2026 00:00:00 +0000

Introduction

Hello, I’m RyotaK (@ryotkak ), a security engineer at GMO Flatt Security Inc.

A while ago, I participated in the Google Cloud VRP bugSWAT, a live hacking event organized by Google.

During this event, I discovered a remote command execution vulnerability in one of Google Cloud’s services. As the vulnerability has now been fixed, I would like to share the technical details in this article.

TL;DR

Google Cloud has a product called Looker, and this product has a feature to manage Git repositories.

Pwning Claude Code in 8 Different Ways

Mon, 12 Jan 2026 00:00:00 +0000

Introduction

Hello, I’m RyotaK (@ryotkak ), a security engineer at GMO Flatt Security Inc.

A few months ago, I came across an interesting behavior while using Claude Code—it executed a command without my approval.

Since I wasn’t using the permission bypass mode, I decided to investigate further to understand why it was able to execute commands without explicit approval.

TL;DR

I discovered 8 ways to execute arbitrary commands in Claude Code without user approval.

Compromising OpenWrt Supply Chain via Truncated SHA-256 Collision and Command Injection

Fri, 06 Dec 2024 00:00:00 +0000

Introduction

Hello, I’m RyotaK (@ryotkak ), a security engineer at Flatt Security Inc.

A few days ago, I was upgrading my home lab network, and I decided to upgrade the OpenWrt on my router.¹ After accessing the LuCI, which is the web interface of OpenWrt, I noticed that there is a section called Attended Sysupgrade, so I tried to upgrade the firmware using it.

After reading the description, I found that it states it builds new firmware using an online service.